Question

A glass full of hot milk is poured on the table. It begins to cool gradually. Which of the following is incorrect?

• A. The rate of cooling is constant till milk attains the temperature of the surroundings.
• B. The temperature of milk falls of exponentially with time.
• C. While cooling, there is a flow of heat from milk to the surroundings as well as from surroundings to the milk but the net flow of heat is from milk to the surroundings and that is why it cools.
• D. All three phenomenon, conduction, convection and radiation are responsible for the loss of heat from milk to the surroundings.

Answer 1

Answer: (A)

The rate of cooling is constant till milk attains the temperature of the surroundings.

Answer 2

The heat from hot milk spread on the table is transferred to the surrounding by conductions. Convections and radiations. According to newton’s law of cooling the temperature of milk falls exponentially with time.